2,544 research outputs found

    Automatic vehicle perpendicular parking design using saturated control

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    International audience—This paper considers the perpendicular reverse parking problem of front wheel steering vehicles. Relationships between the widths of the parking aisle and the parking place, as well as the parameters and the starting position of the vehicle for planning a collision-free reverse perpendicular parking in one maneuver are presented. A nonlinear saturated (tanh-type) feedback steering controller for straight-line tracking is proposed and evaluated. It is demonstrated that the saturated controller, which is continuous, achieves quick steering can be successfully used in solving parking problems. Simulation results and first experimental tests confirm the effectiveness of the proposed control scheme

    Automatic Perpendicular and Diagonal Unparking Using a Multi-Sensor-Based Control Approach

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    International audienceThis paper explores the feasibility of a Multi-Sensor-Based Control (MSBC) approach for addressing forward nonparallel (perpendicular and diagonal) unparking problems of car-like vehicles as an alternative to classical approaches (e.g. path planning based, etc.). The results of individual cases are presented to illustrate the behavior and performance of the proposed approach as well as results from exhaustive simulations to evaluate the convergence and stability. The results presented in this work increase the versatility and validity of our MSBC approach towards a fully autonomous parking system

    Automated Mixed Traffic Vehicle (AMTV) technology and safety study

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    Technology and safety related to the implementation of an Automated Mixed Traffic Vehicle (AMTV) system are discussed. System concepts and technology status were reviewed and areas where further development is needed are identified. Failure and hazard modes were also analyzed and methods for prevention were suggested. The results presented are intended as a guide for further efforts in AMTV system design and technology development for both near term and long term applications. The AMTV systems discussed include a low speed system, and a hybrid system consisting of low speed sections and high speed sections operating in a semi-guideway. The safety analysis identified hazards that may arise in a properly functioning AMTV system, as well as hardware failure modes. Safety related failure modes were emphasized. A risk assessment was performed in order to create a priority order and significant hazards and failure modes were summarized. Corrective measures were proposed for each hazard

    Multi-Sensor-Based Predictive Control for Autonomous Backward Perpendicular and Diagonal Parking

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    International audienceThis paper explores the feasibility of a Multi-Sensor-Based Predictive Control (MSBPC) approach for addressing backward nonparallel (perpendicular and diagonal) parking problems of car-like vehicles as an alternative to more classical (e.g. path planning based) approaches. The results of a few individual cases are presented to illustrate the behavior and performance of the proposed approach as well as results from exhaustive simulations to assess its convergence and stability. Indeed, preliminary results are encouraging, showing that the vehicle is able to park successfully from virtually any sensible initial position

    Improved Visible Light Communication Receiver Performance by Leveraging the Spatial Dimension

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    In wireless communications systems, signals can be transmitted as time (temporal) or spatial variants across 3D space, and in both ways. However, using temporal variant communication channels in high-speed data transmission introduces inter-symbol interference (ISI) which makes the systems unreliable. On the other hand, spatial diversity in signal processing reduces the ISI and improves the system throughput or performance by allowing more signals from different spatial locations at the same time. Therefore, the spatial features or properties of visible light signals can be very useful in designing a reliable visible light communication (VLC) system with higher system throughput and making it more robust against ambient noise and interference. By allowing only the signals of interest, spatial separability in VLC can minimize the noise to a greater extent to improve signal-to-noise ratio (SNR) which can ensure higher data rates (in the order of Gbps-Tbps) in VLC. So, designing a VLC system with spatial diversity is an exciting area to explore and might set the foundation for future VLC system architectures and enable different VLC based applications such as vehicular VLC, multi-VLC, localization, and detection using VLC, etc. This thesis work is motivated by the fundamental challenges in reusing spatial information in VLC systems to increase the system throughput or gain through novel system designing and their prototype implementations

    EVALUATION PAVEMENT DISTRESSES USING PAVEMENT CONDITION INDEX

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    Pavement deterioration is resulted by both environmental and structural causes. It is difficult to maintain the road on the same specification that was owned at the opening and problems start to appear represented in the pavement cracks, holes and undulations and so on. Recognizing defects and understanding their causes helps us rate pavement condition and select cost-effective repairs. Periodic inspection is necessary to provide current and useful evaluation data. It is recommended that ratings be updated every year. Maintenance is an essential practice in providing for the long-term performance and the esthetic appearance of an asphalt pavement. The purpose of pavement maintenance is to correct deficiencies caused by distresses and to protect the pavement from further damage. A condition rating of the pavement will help determine what pavement maintenance technique is necessary. A methodology was proposed to investigate the pavement condition; this study focuses on flexible pavement. A manual survey is performed following ASTM D 6433. The pavement is divided into sections. Each section is divided into sample units. The type and severity of sample distress is assessed by visual inspection of the pavement sample units and the quantity of each distress is measured. Typically, this procedure requires a team of at least two engineers. The pavement evaluation results from the manual PCI survey revealed that all sections of road were fair condition. Considered the section of road that surveyed, describing the condition pavement of the all road. The pavement that has been studied at Koums area would seem to require maintenance. Thick overlay (sometimes called surface treating) is needed in a comprehensive pavement

    How Can Autonomous and Connected Vehicles, Electromobility, BRT, Hyperloop, Shared Use Mobility and Mobility-As-A-Service Shape Transport Futures for the Context of Smart Cities?

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    A smarter transport system that caters for social, economic and environmental sustainability is arguably one of the most critical prerequisites for creating pathways to more livable urban futures. This paper aims to provide a state-of-the-art analysis of a selection of mobility initiatives that may dictate the future of urban transportation and make cities smarter. These are mechanisms either recently introduced with encouraging uptake so far and much greater potential to contribute in a shift to a better transport paradigm or still in an embryonic stage of their development and yet to be embraced as powerful mechanisms that could change travel behaviour norms. Autonomous and connected vehicles are set to revolutionise the urban landscape by allowing machines to take over driving that for over a century has been exclusively a human activity, while electrical vehicles are already helping decarbonising the transport sector. Bus rapid transit has been steadily reinventing and rebranding conventional bus services revitalising the use of the humblest form of public transport, while hyperloop is an entirely new, disruptive, and somewhat provocative, travel mode proposition based on the use of sealed tube systems through which pods could travel free of air resistance with speeds exceeding 1000 km/h. Shared use mobility mechanisms like car-sharing, ride-sharing, ride-sourcing and public bicycles can help establishing a culture for using mobility resources on an as-needed basis, while mobility-as-a-service will take this sharing culture a step further, offering tailored mobility and trip planning packages that could entirely replace the need for privately owned modes of transport

    How the architecture of the CityCar enhances personal mobility and supporting industries

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 121-124).Growing populations, increasing middle-class, and rapid urbanization - for today's urban dweller, all of these escalating factors continue to contribute to problems of excessive energy use, road congestion, pollution due to carbon emissions, and inefficient personal transit. Considering that the average vehicle in a city weighs thousands of pounds, usually caries only one person per trip, and expends significant proportions of its gasoline simply searching for resources such as parking, new efficient and intelligent modes of transportation are in need of exploration. This dissertation presents the design and development of an electric vehicle called the "CityCar" that confronts the aforementioned problems of urban mobility with a novel vehicle architecture. The assembly of the CityCar derives from a subset of "urban modular electric vehicle" (uMEV) components in which five core units are combined to create a variety of solutions for urban personal mobility. Drastically decreasing the granularity of the vehicle's subcomponents into larger interchangeable modules, the uMEV platform expands options for fleet customization while simultaneously addressing the complex rapport between automotive manufacturers and their suppliers through a responsibility shift among their respective subcomponents. Transforming its anatomy from complex mechanically-dominant entities to electrically-dominant modular components enables unique design features within the uMEV fleet. The CityCar for example exploits technologies such as a folding chassis to reduce its footprint by 40% and Robot Wheels that each are allotted between 72 to 120-degrees of rotation to together enable a seven-foot turning circle. Just over 1,000 pounds, its lightweight zero-emitting electric platform, comprised of significantly fewer parts, curbs negative externalities that today's automobiles create in city environments. Additionally, the vehicle platform developed from the assembly of several core units empowers a consortium of suppliers to self-coordinate through a unique modular business model. Lastly, the CityCar specific uMEV confronts problems within urban transit by providing a nimble folding mobility solution tailored specifically to crowded cities. Benefits, such as a 5:1 parking density and its reduced maintenance demands, are especially reinforced in the context of shared personal transportation services like Mobility-on-Demand.by William Lark, Jr.Ph.D
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